GHSA-cj83-2ww7-mvq7 CVE-2024-39316
Rack ReDoS Vulnerability in HTTP Accept Headers Parsing
- Severity
- 6.5 / 10
- Medium · CVSS 3.1
- Exploit chance (EPSS)
- 0.86%
- Chance of exploitation in the next 30 days. Higher than 58.41% of scored vulnerabilities.
- Known exploited
- No
- Not in CISA's catalog
- Weakness
- CWE-1333 Inefficient Regular Expression Complexity
- Fix
3.1.5- Upgrade rack to this version or later
Description
Summary
A Regular Expression Denial of Service (ReDoS) vulnerability exists in the Rack::Request::Helpers module when parsing HTTP Accept headers. This vulnerability can be exploited by an attacker sending specially crafted Accept-Encoding or Accept-Language headers, causing the server to spend excessive time processing the request and leading to a Denial of Service (DoS).
Details
The fix for https://github.com/rack/rack/security/advisories/GHSA-54rr-7fvw-6x8f was not applied to the main branch and thus while the issue was fixed for the Rack v3.0 release series, it was not fixed in the v3.1 release series until v3.1.5.
Affected versions
RubyGems
| Package | Vulnerable | Fixed in |
|---|---|---|
| rack | >= 3.1.0, < 3.1.5 |
3.1.5 |
How to fix
Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.
rack RubyGems → 3.1.5
- bundler
bundle update rack # Gemfile: gem "rack", ">= 3.1.5"
Severity breakdown
CVSS 3.1 6.5
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Weakness
CWE-1333: Inefficient Regular Expression Complexity
The product uses a regular expression with a worst-case computational complexity that is inefficient and possibly exponential.
How to prevent it
- Architecture and Design: Use regular expressions that do not support backtracking, e.g. by removing nested quantifiers.
- System Configuration: Set backtracking limits in the configuration of the regular expression implementation, such as PHP's pcre.backtrack_limit. Also consider limits on execution time for the process.
- Implementation: Do not use regular expressions with untrusted input. If regular expressions must be used, avoid using backtracking in the expression.
- Implementation: Limit the length of the input that the regular expression will process.
References
Advisories
Packages
Other links
Timeline
- Published
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| GHSA-g2pf-xv49-m2h5 Rack::Request accepts invalid Host characters, enabling host allowlist bypass | Medium | Also affects rack |
| GHSA-v6x5-cg8r-vv6x Rack's multipart header parsing allows Denial of Service via escape-heavy quoted parameters | High | Also affects rack |
| GHSA-qfgr-crr9-7r49 Rack: Forwarded Header semicolon injection enables Host and Scheme spoofing | Medium | Also affects rack |
| GHSA-rx22-g9mx-qrhv Rack's improper unfolding of folded multipart headers preserves CRLF in parsed parameter values | Medium | Also affects rack |
| GHSA-q2ww-5357-x388 Rack has Content-Length mismatch in Rack::Files error responses | Medium | Also affects rack |
| GHSA-qv7j-4883-hwh7 Rack::Sendfile header-based X-Accel-Mapping regex injection enables unauthorized X-Accel-Redirect | High | Also affects rack |
| GHSA-8vqr-qjwx-82mw Rack's multipart parsing without Content-Length header allows unbounded chunked file uploads | High | Also affects rack |
| GHSA-x8cg-fq8g-mxfx Rack's multipart byte range processing allows denial of service via excessive overlapping ranges | High | Also affects rack |
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